From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZowDRqoCya9q1eVIBRXIvVLjlIbLLvIvmQT6jN2CqDDfggRRaHxibKmXuaAgUvTu2vYUDpg ARC-Seal: i=1; a=rsa-sha256; t=1525992319; cv=none; d=google.com; s=arc-20160816; b=EtsuVHGpF1x6yJaAQHVhchETbHV+IHSYGuOU7BQspeXHE7YDjMeb8hJdEQI95a9aef a1u812FshnN7M59otRwOdV16JsWMnHgjSDznVx5NaRxWDhiv5UDU19TpmOMtN2SM22XU QnUQ7Qxet01Ua/HRIF1CMPxA4hkhdnc+BrvDLg3Xi72JF2SHH/DNsTDJSjXkIvLwCrpY jg4lh/yQFB09pRt1rUm4MkqTNfwDM1UgPA18bwtrmRcRKw0ioWwR0+DeYW8ac7TaEMKX ZCXK19Dp4Aa71bkM/HBg3wTajtBhKktGsV8ij6U0zXgcLtwo17AFFfQlxbHdpEbSWNiV bkfQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:arc-authentication-results; bh=eghvfPyqR1fMZi9xLWPSsFozaP4PBf2cIGxv781TxSs=; b=Ojdi6NGw/WyfrjrCg+rZI+S67Wa4FtlOS8M1P0u+K262ziOt6B8iXUtEbRLoW7k5k+ S0n2DlXZ6Ldhm1iA2GDX7AyhCQy3rScS8YGysa9YGxysHBfkwQS2NZtZ7wxzsU/qoKos Wmh5He9eANl/1uJaBRpEUs8e/9xWjE5w+O6LMheQfLyjmAHMCeZXTqq1KVTvKjprO4AH zzLwFhuN0dBx2nzOoTjt6kvMU8J321Fc3p9L9OILsSTSntwc0TyxnWLkFnigRfIir7qB dCq0hCVqCNvy1EUOfL6KS8wF5TQLoSrWLi4+aF1rhOinkOxuoD9DdGSv6LiU3INRd3ja UNag== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of jpoimboe@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=jpoimboe@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of jpoimboe@redhat.com designates 66.187.233.73 as permitted sender) smtp.mailfrom=jpoimboe@redhat.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Date: Thu, 10 May 2018 17:45:16 -0500 From: Josh Poimboeuf To: Peter Zijlstra Cc: x86@kernel.org, linux-kernel@vger.kernel.org, Randy Dunlap , Arnd Bergmann , Ingo Molnar , Thomas Gleixner , Greg KH , David Laight , damian Subject: [PATCH v1.2 3/3] objtool: Support GCC 8 switch tables Message-ID: <20180510224516.s7qcjvbolwxkvzqd@treble> References: <60ba92277204856ced0723f7d7ca52c691baace3.1525923412.git.jpoimboe@redhat.com> <20180510084125.GY12217@hirez.programming.kicks-ass.net> <20180510124424.uauk7p4uzsfon4hs@treble> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20180510124424.uauk7p4uzsfon4hs@treble> User-Agent: NeoMutt/20180323 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1600046846156782249?= X-GMAIL-MSGID: =?utf-8?q?1600118922778874504?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Add some additional checks to the switch jump table logic. This fixes the following warnings with GCC 8: drivers/block/virtio_blk.o: warning: objtool: virtio_queue_rq()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+72 net/ipv6/icmp.o: warning: objtool: icmpv6_rcv()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64 drivers/usb/core/quirks.o: warning: objtool: quirks_param_set()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+48 drivers/mtd/nand/raw/nand_hynix.o: warning: objtool: hynix_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+24 drivers/mtd/nand/raw/nand_samsung.o: warning: objtool: samsung_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+32 drivers/gpu/drm/nouveau/nvkm/subdev/top/gk104.o: warning: objtool: gk104_top_oneinit()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64 Reported-by: Arnd Bergmann Reported-by: kbuild test robot Signed-off-by: Josh Poimboeuf --- v1.2: replaced 'sizeof(long)' with '8' to fix cross-compilation of the 64-bit target on a 32-bit host tools/objtool/check.c | 24 ++++++++++++++++++++++-- 1 file changed, 22 insertions(+), 2 deletions(-) diff --git a/tools/objtool/check.c b/tools/objtool/check.c index 14daf6a27d9f..9bb04fddd3c8 100644 --- a/tools/objtool/check.c +++ b/tools/objtool/check.c @@ -810,17 +810,28 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn, struct rela *rela = table; struct instruction *alt_insn; struct alternative *alt; + struct symbol *pfunc = insn->func->pfunc; + unsigned int prev_offset = 0; list_for_each_entry_from(rela, &file->rodata->rela->rela_list, list) { if (rela == next_table) break; + /* Make sure the switch table entries are consecutive: */ + if (prev_offset && rela->offset != prev_offset + 8) + break; + + /* Detect function pointers from contiguous objects: */ + if (rela->sym->sec == pfunc->sec && + rela->addend == pfunc->offset) + break; + alt_insn = find_insn(file, rela->sym->sec, rela->addend); if (!alt_insn) break; /* Make sure the jmp dest is in the function or subfunction: */ - if (alt_insn->func->pfunc != insn->func->pfunc) + if (alt_insn->func->pfunc != pfunc) break; alt = malloc(sizeof(*alt)); @@ -831,6 +842,13 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn, alt->insn = alt_insn; list_add_tail(&alt->list, &insn->alts); + prev_offset = rela->offset; + } + + if (!prev_offset) { + WARN_FUNC("can't find switch jump table", + insn->sec, insn->offset); + return -1; } return 0; @@ -887,7 +905,9 @@ static struct rela *find_switch_table(struct objtool_file *file, struct instruction *orig_insn = insn; text_rela = find_rela_by_dest_range(insn->sec, insn->offset, insn->len); - if (text_rela && text_rela->sym == file->rodata->sym) { + if (text_rela && text_rela->sym == file->rodata->sym && + !find_symbol_containing(file->rodata, text_rela->addend)) { + /* case 1 */ rodata_rela = find_rela_by_dest(file->rodata, text_rela->addend); -- 2.17.0